1. Global Variables
in LabVIEW Tutorial by Harris Pharr

2. What are Global variables?
Global variables are used to access and pass data among several VI’s that run simultaneously.
Can control multiple VI’s and read their results from one front panel.

3. JK-Flip Flop
Global Variables control input values and clock along with global stop button to control a JK-flip flop running via a JK.VI and a sub via JK_sub.VI.
Output values displayed on VI’s of all 3 front panels of each respective VI.

4. JK FF Truth Table
To the right is a JK FF truth table which can be verified in with using the following VI.

5. Front Panel VI
On the left are the Global Variable Input controls and on the top right is the JK VI and SUB VI front panels.

6. Block Diagram
The top diagram is the simplified JK sub .VI and on the bottom is the JK VI. The global variables all have Global indicated on their label.

7. VI in Action
You can verify the JK FF’s truth table with this video showing the VI being operated from the Global variable front panel.

8. Tutorial can be found on my website at